The use of bone screw anchors to hold sutures is a widely accepted practice in shoulder or knee repair and fixation of soft tissue such as ligaments, cartilage and tendons to bone. Ideally the suture anchor is easy to install and provides a solid reliable way to fix the sutures to the bone. The bone has a hard outer cortical shell with a softer underlying region of cancellous bone tissue. The anchor must hold sutures after thousands of repetitive motions tensioning and relaxation until the ligament or tendon repair has time to heal and secure itself to the bone and muscle tissue.
Older style bone anchors had an external eyelet to allow the sutures to be fed through after the screw was driven into the bone. This left the eyelet exposed in the soft muscle tissue.
Later versions of bone anchors have the sutures inserted inside the screw tip well inside the bone. This allows the screw outer end to stay flush with the cortical bone outer surface. The sutures can pass inside in some hollow screws from the tip to the outer surface. A main problem is how to thread the bone anchor into the bone. In some suture anchor systems there is a self-driving feature that has a punch tip that can be malleted into the bone. Once started, the anchor must be rotated to thread it into the bone. The ends of the sutures are often dangling in the way.
Ideally the procedure should insure the bone anchor is easily installed without having the sutures interfering with the anchoring.
The present invention provides a threaded bone anchor that is easy to install wherein the sutures are held securely with the bone anchor, but wherein the ends of the sutures are contained inside the delivery device.